The objective of this Career Development Award is to facilitate Dr. Miller's transition to independent investigator, with an emphasis on developmental research that will inform questions related to children's health-related decision making and child assent. The achievement of this long-term goal requires integration of knowledge in the areas of pediatric psychology, pediatric ethics, and developmental psychology and additional training in qualitative analysis and advanced statistics. Dr. Miller, a postdoctoral fellow in pediatric psychology at The Center for Research Integrity, will address these training needs through coursework, seminars, and mentored research. Dr. Miller has selected a highly qualified team of mentors and collaborators, representing disciplines that are relevant to her training needs and research plan. Dr. Miller's research plan is designed to inform questions related to how children achieve independence for the management of a chronic illness, which often requires a series of complex decisions that must be made on a daily basis. The primary construct of interest is parent-child collaborative treatment decision making, which is conceptualized as an important precursor to independent and effective management of the treatment regimen for a chronic illness. Study 1 will utilize focus groups to explore the construct of collaborative treatment decision making from the perspective of children with a chronic illness and their parents and create an item pool that assesses relevant domains of collaborative decision making. Study 2 will construct a reliable instrument that measures collaborative treatment decision making and will establish the preliminary construct validity of the instrument. Study 3 will examine the associations among collaborative treatment decision making and selected developmental, psychosocial, and social-ecological variables. These three studies will lay the groundwork for future longitudinal research that examines developmental trajectories and mechanisms related to collaborative treatment decision making, as well as health-related outcomes. Relevance: Chronic illnesses affect 7% to 18% of children and may persist into adulthood or lead to secondary conditions. The transition to greater independence for health-related decisions during childhood and adolescence is relevant to health outcomes and may provide the foundation for effective disease management during adulthood, making it a critical area of empirical investigation.